An implantable medical device having a transceiver for transmitting/receiving wirelessly transmitted data, which is turned off or switched into an energy-saving rest state between individual data transmissions via the transceiver and having a waking unit which is implemented to switch the transceiver by a waking signal from its turned-off state or its rest state into its fully operational state, the waking unit having a low-power receiver and a waking control unit of which the low-power receiver is implemented to monitor multiple predefined frequency ranges in such a way that in case of a transmission of sufficient signal strength in one of the frequency ranges, it generates an output signal and outputs it to the waking control unit and of which the waking control unit is implemented to analyze output signals of the low-power receiver and output a waking signal to the transceiver which switches it on or to fully operational.